Mechanism for setting the needles or indicating heands of hermetically sealed voltmeter or analogous instruments



1. KEROES MECHANISM FOR SETTING THE NEEDLES OR INDICATING HANDS OF HERMETICALLY SEALED VOLTMETER OR ANALOGOUS INSTRUMENTS Filed July 26, 1946 FIG.4-

HERBERT 1K EROES INVENTOR.

Patented Nov. 1 4, 1956 MECHANISM FOR SETTING THE NEEDLES R INDICATING HANDS 0F HERMETI- CALLY SEALED VOLTMETER OR ANALO- GOUS INSTRUMENTS Herbert 1. Heroes, llrvington, N. J., assignor to The llaven'ilompany, Newark, N. J., a corporation of New Jersey Application July 26, 1946, Serial No. 686,310

(Claims. (o1. 171-95) This invention relates to volt meters and like instruments and more particularly to means for manually setting the needles or indicating hands of such instruments.

An object of the present invention is to provide means for setting the needles or indicating hands of hermetically sealed voltmeters or analogous instruments for the purpose. of correcting inaccuracies in the normal rest position of the hand or needle from the exterior of the instrument housing by means of which the indicating hand when set to the prescribed rest point shall not deviate from that point due to changes in temperature or changes in atmospheric pressure; which setting means includes an adjustment mechanism and linkage eXteriorly of the instrument housing that are substantially unaffected by temperature or atmospheric pressure change.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a mechanism for se ting the needle or indicating hands of hermetically voltmeters or analogous instruments of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings:

Figure l is a front elevation of the improved means for setting the needles or indicating hands of hermetically sealed voltmeters or analogous instruments.

Figure 2 is a rear view of the face or front plate showing a part of said setting mechanism in side elevation.

Figure 3 is a fragmentary vertical section taken on line 3--3 of Figure 1.

Figure 4 is a vertical section taken on line 44 of Figure 3.

Referring more particularly to the drawings, a voltmeter of approved construction is shown inthe drawings, but it is to be understood that the invention applicable for use with any anal-- ogous type of instrument without departing from the spirit of the present invention.

The volt meter 1 in its normal housing 2 is enclosed in a hermetically sealed housing 3, and it includes the usual dial 4 carrying the desired or necessary indicia indicated at 5. The indicia 5 are visible through a hermetically sealed window 6 in the housing 3. A needle or indicating hand 'I co-operates with the indicia in the usual manner and this needle I is carried and operated slot I! cut in the segmental gear [8.

by the usual type of operating mechanism in- .icated at 8 which includes a pendulous element 9 which contacts and operates the spring 9' of the operating mechanism. The pendulous element 9 has an opening H3 therein having an upper portion reduced in size as clearly shown in Figure 4 of the drawings.

The needle setting means includes a pin H which has a tapered semi-resilient sleeve [2 mounted on its inner end. The pin l I and sleeve I! extend into the reduced portion of the opening If! in the pendulous element 9 and the sleeve I2 engages the side walls of the opening l0.

The pin 5 5 extends outwardly through the hermetically sealed housing 3 through an opening i3 and is formed upon or attached to a disc [4. The disc [4 is attached in air tight connection with a metallic bellows l5 which is attached to the housing 3 about the opening 13 in fluidtight engagement, thus the pin H passes outwardly through the hermetically sealed housing 3 without disrupting the fluid tightness of the housing.

A short pin or stud l 6 is carried axially by the outer side of the disc M and engages in a radial The segmental gear I8 is carried by a face plate [9 for rotary movement.

The face plate I9 is attached to the housing 3 and the housing 2 of the voltmeters I by screws or bolts which extend through the holes 2| in the housing 2.

A pinion 22 is carried by one end of a stub, shaft 23, and the stub shaft 23 is rotatably carried by and extends through the face plate 19.

The outer end of the stub shaft 23 has a head 24 thereon which is suitably spaced from the face plate [9 by spacing washers 25 so as to allow rotation of the stub shaft 23 and pinion 22, but prevent their accidental rotation. The head 24 is provided with a tool receiving slot in its outer face to facilitate rotation of the stub shaft 23 and pinion 22.

The pinion 22 meshes with the teeth of the segmental gear 18 to rotate the gear l8 by rotation of the pinion for rocking the pin H toadjust the needle I.

When the hermetically sealed housing 3 is at-. tached to the face plate ES by means of the screws 20, the bellows I5 is compressed longitudinally by a small amount, thereby forcing the semispherically shaped outer end of the stud [6 into contact with the inner side of the face plate l9. As the stud i5 is wobblecl from side to side by rotation of the segmental gear Hi the semispherical outer end of the stub it will describe a 3 smooth rolling and sliding action against the inner surface of the face plate 19.

The degree of compression of the bellows I5 is provided so that an increase in atmospheric pressure or a decrease in ambient temperature will not materially further compress the bellows and force the semi-spherically shaped outer end of the stud [6 out of contact with the face plate l9; that is when the needle or indicating hand 1 has been set with a desired degree of accuracy relative to its normal rest position, variations in atmospheric pressure or ambient temperature will not cause a change in the length of the bellows l5 which if permitted would change the effective length of the pin I I thereby causing a movement of the pendulous element 9 and the needle or indicating hand I.

The segmental gear l8 has a pair of stop members 28 attached to its inner surface which extend over the adjacent teeth of the segmental gear, and engage the teeth of the pinion to limit the rotary movement of the segmental gear in either direction.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is:

1. The combination with a volt meter or like instrument including a dial and an indicating hand for co-operation with said dial, of a hermetically sealed housing enclosing said volt meter, means for setting said indicating hand to desired positions relative to its normal rest position, including an indicating hand moving pin extending through said housing, a sealed bellows about the portion of said pin exteriorly of said sealed housing, said bellows attached to the housing with a fluid tight seal, a stud carried by said bellows and extending outwardly from the outer sealed end of the bellows, a face plate engaged by the outer end of said stud, said face plate attached to said housing in such manner as to pro vide limited compression of said bellows through its contact with said stud, and manually operated means carried by said face plate and engaging said stud to cause a wobbling movement of said pin through its connection with said bellows in moving said indicating hand, said stud having a semi-spherical outer end for slidable engagement with said face plate.

2. The combination with a volt meter or like instrument including a dial and an indicating hand for co-operation with said dial, of a hermetically sealed housing enclosing said volt meter, means for setting said indicating hand to desired position relative to its normal rest position, including an indicating hand moving pin extending through said housing, a sealed bellows about the portion of said pin exteriorly of said sealed housing, said bellows attached to the housing with a fluid tight seal, a stud carried by said bellows and extending outwardly from the outer sealed end of the bellows, a face plate engaged by the outer end of said stud, said face plate attached to said housing in such manner as to provide limited compression of said bellows through its contact with said stud, and manually operated means carried by said face plate and engaging said stud to cause a wobbling movement of said pin through its connection with said bellows in moving said indicating hand, said stud having a semi-spherical outer end for slidable engagement with said face plate, and stop means for limiting the degree of movement of said manually operated means.

3. The combination with a volt meter or like instrument including a dial and an indicating hand for cooperation with said dial, of a hermetically sealed housing enclosing said volt meter, means for setting said indicating hand to desired position relative to its normal rest position, including an indicating hand moving pin extending through said housing, a sealed bellows about the portion of said pin exteriorly of said sealed housing, said bellows attached to the housing with a fluid tight seal, a stud carried by said bellows and extending outwardly from the outer sealed end of the bellows, a face plate engaged by the outer end of said stud, said face plate attached to said housing in such manner as to provide limited compression of said bellows through its contact with said stud, and a segmental gear movably mounted on the inner surface of said face plate, manually operated means carried b said face plate for engaging and moving said segmental gear, means on said segmental gear for receiving said stud therethrough for contact with said plate, and said stud having a semi-spherical outer end for slidable engagement with said face plate.

4. The combination with a volt meter or like instrument including a dial and an indicating hand for cooperation with said dial, of a hermetically sealed housing enclosing said volt meter, means for setting said indicating hand to desired position relative to its normal rest position, including an indicating hand moving pin extending through said housing, a sealed bellows about the portion of said pin exteriorly of said sealed housing, said bellows attached to the housing with a fluid tight seal, a stud carried by said bellows and extending outwardly from the outer sealed end of the bellows, a face plate engaged by the outer end of said stud, said face plate attached to said housing in such manner as to provide limited compression of said bellows through its contact with said stud, and a segmental gear movably mounted on the inner surface of said face plate, manually operated means carried by said face plate for engaging and moving said segmental gear, a radial slot on said segmental gear in axial alignment with said stud for receiving said stud therethrough for contact with said plate, and said stud having a semi-spherical outer end for slidable engagement with said face plate.

5. The combination with a volt meter or like instrument including a dial and an indicating hand for cooperation with said dial, of a hermetically sealed housing enclosing said volt meter. means for setting said indicating hand to desired position relative to its normal rest position, including an indicating hand moving pin xtending through said housing, a sealed bellows about the portion of said pin exteriorly of said sealed housing, said bellows attached to the housing with a fluid tight seal, a stud carried by said bellows and extending outwardly from the outer sealed end of the bellows, a face plate engaged by the outer end of said stud, said face plate attached to said housing in such manner as to provide limited compression of said bellows through its contact with said stud, and a segmental gear movably mounted on the inner surface of said face plate, a stub shaft passing through said face plate, a pinion fixedly connected at one end of said stub shaft, rotation means fixedly connected to the other end of said stub shaft whereby when said rotating means is moved the said pinion engages and moves the segmental gear, a radial slot in said segmental gear in axial alignment with said stud for receiving said stud therethrough for contact with said plate and to transmit movement thereto to impart a wobbllng movement to the pin attached thereto by the bellows and sealed end, and said stud having a semi-spherical outer end for slidable engagement with said face plate.

HERBERT I. KEROES.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number Great Britain Sept. 10, 1943 

